Cover sealed leakproof carton



United States Patent 3,261,536 COVER SEALED LEAKPROOF CARTON Kenneth D. Bixler, Huntington, N.Y., assignor to Diamond International Corporation, New York, N.Y., a corporation of Delaware Filed Nov. 9, 1964, Ser. No. 409,717 9 Claims. (Cl. 229-37) The present invention relates generally to cartons utilized for packaging pu'lverulent, flaky and granular materials such as washing powders, soap flakes, salt, flour, etc., as well as liquid and/ or liquid-containing products, and is more particularly directed to an improved closure assembly and blank for producing a substantially completely sealed glued-end carton for preventing pulverulent or fluent materials from sifting out of the packages.

Many of the materials presently being packaged are of the nature to be harmed or deteriorate when subjected to excess moisture due to changing humidity conditions, for example. In order to prevent pulverulent material from sitting out of the cartons, or to protect the product from changing atmospheric conditions, many packaging cartons incorporate waterproof liners or sacks disposed in the carton, oftentimes the package is wrapped with a transparent paper or is dipped in a sealing material.

Any of the methods heretofore contemplated add to the expense of the package and increase the costs imposed on the ultimate consumer.

A primary object of the present invention is to provide an improved carton and blank in which novel means are provided for producing delaminable sealing corner gussets for the closure assembly.

Another object of the present invention is to provide a novel glued seal at the corners of a glued-end carton from which sealing webs are produced.

A still further object of the present invention is to provide a novel closure assembly in which delaminable sealing gussets are not only provided at the corners of the closure assembly but which extend substantially the entire extent of free edges of a glued-end closure to provide an improved seal.

Another object of the present invention is to provide a novel glued-end closure without appreciable costs to the ultimate consumer.

These together with other and more specific objects and advantages of the invention will become apparent from a consideration of the following description when taken in conjunction with the accompanying drawings forming a part thereof, wherein:

FIG. 1 is a fragmentary plan view of a carton blank including closure flaps for producing the novel closure assembly of the invention;

FIG. 2 is an enlarged fragmentary plan view of a portion of the blank of FIG. 1;

FIG. 3 is a section taken substantially on the plane of line 33 of FIG. 2;

FIG. 4 is a section taken on the plane of line 4-4 of FIG. 2;

FIG. 5 is a perspective view of the end portion of a carton directed from a blank of the character shown in FIG. 1, prior to manipulating or closing the end closure assembly;

FIG. 6 is a perspective view showing by means of phantom lines the glue-applying rollers for applying a glue pattern to the end closure assembly which is shown partially closed;

FIG. 7 is a perspective view, on a reduced scale, of the end closure assembly partially closed, and illustrating by a direction arrow the last manipulative step completing the closing of the carton;

FIG. 8 is a fragmentary plan view of another embodiment of the invention illustrating a blank which will produce gusset sealing webs extending the entire length of the free edges of the closure flaps of the closure assembly;

FIG. 9 is an enlarged section taken substantially on the plane of line 9-9 of FIG. 8;

FIG. 10 is a perspective view on a slightly enlarged scale of a carton erected from the blank of FIG. 8;

FIG. 11 is a perspective view showing the manner in which the inner closure flaps are closed and the outer closure flaps are opened for the first purpose of delaminating sealing gusset webs;

FIG. 12 is an enlarged section taken substantially on the plane of line 12-12 of FIG. 11;

FIG. -13 is a perspective view showing the end closure assembly of the blank of FIGS. 810 in a closed condition;

FIG, 14- is a plan view of still another blank, similar to FIG. 1 showing still another embodiment of the invention;

FIG. 15 is a perspective view of the upper portion of a carton erected from the blank of FIG. 13;

FIG. 16 is a perspective view showing a manipulative step accomplished after that shown in FIG. 14 to illustrate the manner in which the closure assembly is being closed;

FIG. 17 is a perspective view showing a still further manipulative step; and

FIG. 18 is a perspective view showing the manner in which the final application of glue is made prior to the final manipulation of the outermost closure flap.

Referring to the drawings in detail, and first consid ering FIG. '1, a planar blank produced from any suitable material, i.e. paperboard, boxboard, etc., is indicated generally at 10. The paperboard material is of such a character that layers thereof can be delaminated or pulled from adjacent layers as is conventional in the art. In this regard, conventional paperboard stock generally has a grain structure, and the blanks produced from the raw stock of paperboard are generally disposed or laid out along the grain of the paperboard stock.

The blank 10, in this preferred embodiment, comprises alternately disposed pairs of rectangular wall panels 12, 14 and 16, 18 connected to each other on mutually parallel fold lines 20, 22 and 24. The wall panel I18 includes a free side edge margin 26 and the wall panel 12 includes a fold line side marginal edge 28 to which is connected an elongated narrow glue flap or panel '30. In this regard, the glue ilap panel 30, as is conventional, could be formed along the free side marginal edge of the wall panel 18 and thus fold line 28 would be provided along the side edge of the panel 18 and a free marginal edge would be provided along the side of the wall panel 12; see FIG. 8, for example.

The panels 12-18 and 30 have formed transversely thereacross as indicated generally at 32, a linear, marginal fold line which consists of colinear fold line segments 34- 42 normal to panels 12-18 and 30 and respectively overlying the same.

Hingedly connected to the marginal fold line 32 and indicated generally at 44 is an end closure assembly comprising pairs of alternately disposed outer and inner closure flaps 46, 48 and 50, 52, respectively, connected to fold line segments 46, 36, and 38, 34, respectively. Hingedly connected to the segmental fold line 42 adjacent one side of the closure flap 46 is a glue tab 54.

At least one pair of the closure flaps, i.e. 46, 48 in this exemplary embodiment, include a free side marginal portion 56, 58 and 60, 62, respectively.

It will be apparent to those skilled in the art, that the structure to presently be described could be incorporated in the other :pair of closure flaps 50, 52 and the folding sequence of the end closure assembly would accordingly be changed; see, for example, FIG. 14. Inasmuch as the structure to produce a gusset-type sealing web is identical at the respective free margins of the flaps 46 and 48, as seen in FIGS. 2 and 3, only one portion to produce a single gusset-type sealing web will be described in specific detail, i.e. for example the gusset-type web which is produced at the upper end of the fold line 20, i.e. between the adjacent margins of flaps 46 and 50.

The free margin 58 continues in a colinear cut-score line portion 64 which extends partially into the surface of the blank as clearly seen in FIG. 3. The cut-score portion 64 is colinear to the free edge 58 and fold line 20 and defines one free edge of the gusset-type sealing web to subsequently be described. Extending angularly and transversely through the closure flap 46 at the juncture between the free edge 58 and cut-score line 64 is an angular nick 66 which extends laterally into the closure flap 46. The grain of the blank will extend in the general direction illustrated by the dotted direction arrow on FIG. 2. Extending transversely through opposite surfaces of the closure flap 46 in angularly or diverging relationship from the free margin 48 and cut-score line 64 is a cut-slot 68 (see FIG. 4), which extends above and below the inner terminal end of the nick 66.

As previously mentioned, the cuts and nicks as well as the cut-score lines at the margin '56 of the closure flap 46 and below the free margins 60 and 62 of the closure flap 48 are identical to those just described in detail, and, accordingly, similar reference characters are applied to FIG. 1 to identify similarly functioning structure.

The blank of FIG. 1 is assembled as a rectangular tube by applying glue to the glue flap panel 30 and the tab 54 thereof, and securing these portions to the inner surface of wall panel 18 and closure flap 52, respectively, as seen in FIG. 5. Although the closure assembly at the opposite end of the blank is not shown in detail, a configuration similar to that illustrated in FIG. 1 or of any other suitable character can be used thereat.

The rectangular tube produced from the bank, after it has been .assembled is foldable fiat as is conventional in the art.

The bottom closure assembly of the carton will be closed after the wall panels 12, 14 and 16, 18 are disposed in mutually parallel relationship as seen in FIG. 5, and the carton will be filled with the product to be packaged, i.e. flour, salt, or other pulverulent material. It will be noted that the closure flaps 46-52 extend in coplanar relationship with respect to the wall panels 12-18, respectively.

The inner closure flaps 50, 52 are initially disposed in coplanar relationship as seen in FIG. 6, i.e. folded inwardly as described in the patents to Gannon et al. 1,723,149 and 1,723,150. When the inner closure flaps 50, 52 are folded inwardly toward each other on any suitable equipment, this inward folding is resisted by the uncut portion extending along the cut-score lines 64. When this resistance to inward folding occurs, the portion of the inner layer of material flanked by the cut-score lines 64 will delaminate away from the inner surface of the respective outer closure flaps 46 and 48 and the transverse nicks 66 will promote or initiate this delamination inwardly toward the cut-slots 68. As the inward folding continues, i.e. along the general grain of the blank, delamination of the inner layer of material will actually jump or skip from the nick 66 to the cut-slots 68, and then the cut-slots 68 will promote delamination therealong, i.e. resistance to delamination is reduced, and thus produces a substantially angular margin for a sealing gusset web 70. Delamination of the sealing gusset web 70 produces a substantially triangular gusset-type sealing web as clearly seen in FIG. 6.

The just-mentioned cuts-score-nicks, and cut-slots 66 and 68 will ensure and promote uniformly delaminated sealing webs 70 and substantially eliminate poorly sealing corners. Next, the outer closure flaps 46 and 48 are disposed in outwardly extending coplanar relationship as seen in FIG. 6, being supported on folding bars or support bars B, for example. A glue mechanism comprising a shaft 72 and longitudinally spaced glue applying rollers 74, 76, 78 and will apply strips of a suitable adhesive material 74', 76, 78' and 80', respectively spaced outwardly from the sealing webs 70 and the portions 70' from which they are delaminated.

Next, one or the other of the outer closure flaps, i.e. 46 or 48 is folded into juxtaposed overlying relationship with respect to the inner closure flaps 50 and 52; for example, closure flap 46 as shown in FIG. 7, and adhesive from the strip 78' will engage the adjacent sealing webs 70 formed from the closure flap 46 and the portion 70' thereof from which these webs are delaminated.

A layer of adhesive 81 is applied to the outer surface of the closure flap 46, and next the closure flap 48 is folded in overlying relationship with respect to the closure flap 46 to accordingly provide glue on the sealing webs 70 and recess portions 70' from which the webs were delaminated accordingly providing a complete seal at all four corners of the carton.

In as much as the portions 70' from which the sealing webs were delaminated are relatively thinner than those portions of the blank, the outer free edges horde-ring the recessed portions 70' will fold downwardly or feather into the upper bordering margin of the carton as indicated at 82. This ensures a proper seal not only at the corners but at adjacent portions of the free marginal edges of the outer closure flaps 46 and 48.

Referring to FIGS. 8-13, and first considering FIG. 8, another embodiment of the invention is disclosed. In order to relate the comparable functioning portions of the embodiment of FIGS. 8-13 with those of the previously described embodiment, similar reference characters having the prefix will be utilized.

An upper fragmentary portion of a planar blank, produced from any suitable paperboard material or the like, is indicated generally at and comprises alternately disposed pairs of wall panels 112, 114, 116 and 118 connected on mutually parallel fold lines 120, 122 and 124. In this instance, the wall panel 112 includes a free edge margin 126 and the wall panel 118 includes a side marginal fold line 128 to which is hingedly connected a glue flap panel 130.

The wall panels 112-118 and glue flap panel 130 are bordered by a marginal fold line indicated generally at 132 which comprises colinear fold line segments 134-142, respectively.

Hingedly connected to the segmental fold lines 134- 142 are inner and outer closure flap panels 150, 152 and 146, 148 as well as a glue tab 154 hingedly connected to the segmental fold line 142 bordering the glue flap panel 130 and comprises a closure assembly indicated generally at 144.

The combined length of the inner closure flaps 150, 152, as indicated by the dimensioned line L in FIG. 1, is at least equal to the width W of the outer closure flaps 146, 148. This dimensional relationship is merely il-lustrative, but, as will subsequently be described in detail, it is for the purpose of producing gusset-type sealing webs which will extend the entire width W of the outer closure flaps 146, 148 to accordingly form a seal extending along the entire free marginal edges of the inner sealing flaps to provide a seal along the entire length thereof for further assurance against sifting of the pulverulent material out of the package.

At least one pair of the closure flaps, in this instance inner closure flaps 150, 152, include free marginal edges 156, 158 and 160, 162 flanking the respective closure flaps 152 and 150. The marginal edges 156 merge into colinear cut-score lines 164 which terminate at the marginal fold line 132 as do the cut-score lines 64 with respect to the marginal fold 32 of the previously described embodiment. The cut-score lines 164 extend partially into the surface of the blank as clearly seen in FIG. 9, and as seen in FIG. 8, cut-nicks extend transversely through the closure flaps 150 and 152 and as indicated at 166 and have the same function as the cut-nicks 66 of the previously described embodiment. Extending transversely through the closure flaps 150, 152 and spaced from the cut-nicks 166 are cut-slots 168 which extend intermediately or on opposite sides of the inner terminal end of the cut-nicks 166. The cut-slots 168, as seen for example in FIG. 9, will ensure the delamination of a relatively elongated sealing-gusset web 170 from the inner surface of the respective closure flaps to form a thinner or recessed portion 170' as in the previously described embodiment. Considering FIG. 10, the blank of FIG. 8 is assembled as a rectangular tube, and after the bottom closure assembly (not shown) is closed, a pulverulent product or the like is disposed in the tubular carton. Next, the outer closure flaps 150, 152 may be moved outwardly as disclosed in the patent to Wesselman #2,107, 096, for example, which causes delamination at the nicks 166, the grain of the blank promoting delamination over to the cut-slots 168 whereby the elongated gusset-type sealing Webs 170 are produced. Next, the inner closure flaps 146, 148 are folded into overlying substantially coplanar relationship as seen in FIG. 11 and while the outer closure flaps 150, 152 will be folded outwardly into coplanar relationship on support bars B. It will be noted that the inner ends 171 of the gussettype sealing webs 170, i.e. extending along the free margins normal to the fold lines 136 and 140 and the inner ends will overla each other.

Although not shown, the entire blank, i.e. including the inner surfaces of the closure flaps, may be pre-coated or laminated with a suitable heat-responsive adhesive material or heat sealable material of any suitable character. When the panels are oriented in the condition shown in FIG. 11, a heat-seal bar H or equivalent means, i.e. hot air, etc. may be placed in the path of travel of the carton being closed, i.e. assuming that a conventional conveyor line or closure apparatus is being used for the purpose of closing the lids of the closing assemblies, and the adhesive material at the overlapped webs 170 is activated. Further, the heat-responsive adhesive will also be incorporated on the exposed surfaces of the other closure flaps and thus the outer closure flaps 150 or 152 may be then folded in overlying relationship with respect to the closure flaps 146, 148 to produce a carton which is not only sealed at each of the corners of the closure assembly but which has sealing guessets overlapped at the rear ends and extending along the entire length of the free edges of the inner closure flaps.

As mentioned with respect to the previously described embodiments of FIGS. l-6, the recessed portions 170 from which the sealing webs 170 are delaminated, will provide a thinned-out or feathered edge portion 182 which will merge or overlap the adjacent fold line 136, for example, as clearly seen in FIGS. and 13.

Referring to FIGS. 14l8, a blank similar to that disclosed in FIGS. 1-8 is indicated generally at 310 and although the wall panels have been reoriented, this blank has substantially identical structural and functional characteristics with respect to those portions described in detail with respect to FIGS. 1-8. Therefore, only the structure which has been modified will be described in detail and identically functioning structure, i.e. appearing in FIG. 1, for example, will be identified with identical reference numerals as used in FIG. 1.

The inner closure flaps 350 and 352 have extending therethrough substantially rectangular apertures 351 and 353, respectively. The first inner closure flap 346 has extending transversely the-reacross colinear segmental fragmentary fold lines 355, 357 and 359 which define outer and inner transverse panel segments 361 and 363. The panel segment 361 includes a pair of spaced, sealing-ear portions 365 and 367 which extend into the panel sega 6 ment 363 and are formed by cut-lines 369 and 370 flanked by the segmental fold lines 355-359.

The structure incorporated in the end closure assembly indicated generally at 354, in addition to incorporating gusset-type sea-ling webs, utilizes the teachings of applicants copending application Serial No. 251,258 filed January 14, 1963, issued as US. Letters Patent #3,163,347 on December 29, 1964.

The blank of FIG. 14 is assembled as a rectangular tube, filled with a product to be packaged and the inner closure flaps 350, 3 52 are folded inwardly in coplanar relationship while the outer closure flaps 346 and 348 are folded outwardly as seen in FIG. 15. This folding may be accomplished by a conventional folding bar F, for example. Next, a glue applying roller G, similar to that of FIG. 6, may be utilized to apply strips of a suitable adhesive material outwardly of the gusset-type sealing webs which have been formed due to manipulation of the closure assembly to the condition shown in FIG. 15 as previously described in detail with respect to FIGS. '18. The roller G will apply a strip of adhesive at the fold line of cover panel 48.

The apertures 351 and 353 will be disposed in longitudinally extending alignment and the distance D from the edges of the apertures 35 1, 353 to the fold line 40 will be substantially equal to the distance D, i.e. the width of the panel segment 363.

Next, referring to FIG. 16, fold bars F, F" fold the panel segments 363 rearwardly or outwardly in a sense into overlying relationship with respect to the panel segment 362 and the lock noses 367, 369 are folded out of the panel segment 362. Next, as seen in FIG. 17, the fold bars F, F" together with the fold bar F insert the lock noses 367, 369 into apertures 351, 353, respectively, and the panel segments 361, 363 are disposed in substantial coplanar relationship as seen in FIG. 18. Inasmuch as the lock noses 367, 369 extend beneath the inner closure flaps 350, 352, a substantial underlying base is provided whereby a glue roll G can apply a strip of glue adjacent the free edge of panel segment 363, and finally the panel 48 will be folded into overlying relationship with respect to panel segments 361, 363. Additional pressure can be readily applied to the outer surface of the closure flap 48 due to the solid base formed by the inner engagement between the inner closure flaps and closure flap 346. These lock noses also sealingly-engage beneath the flaps with which they are engaged.

Briefly in review, in FIGS. 1-8, there has been disclosed a novel blank and end closure assembly which novel means are provided for forming a gusset-type sealing web at all of the corners of a closed and sealed carton of the glue-end type. In FIGS. 9-13, the sealing web will extend along the entire free edges of the inner closure flaps utilizing the same principles of delamination of the gussettype sealing web, and finally in FIGS. 1418, means are provided for producing an exceptionally firm base to ensure proper gluing of the end closure assembly without the use of internal jigs or the like.

It will be obvious to those skilled in the art that various changes may be made without departing from the scope of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification but only as indicated in the appended claims.

What is claimed is:

1. In a one-piece, planar, delaminable, carton blank having an inner and outer surface and for producing a glued end carton comprising pairs of alternatively disposed rectangular wall panels connected on mutually'parallel fold lines and a continuous, linear marginal fold line extending transversely of one end of said wall panels, and an end-closure assembly comprising cut-and-scored portions for producing a gluedend, comer-sealed carton, comprising:

pairs of alternately disposed end closure flaps hingedly connected to said marginal fold line,

one pair of said end closure flaps comprising side margins in colinear relation to said mutuallyparallel fold lines and including a free terminal portion extending between said inner and outer surfaces and terminating in a base portion extending partially through said outer surface of said blank and terminating at said marginal fold line,

said one pair of end closure flaps including minute lateral nick portions extending through said [flaps adjacent the juncture between said free terminal portions and base portions of said side margins for only initiating delamination of a sealing gusset therebelow during manipulation and closing of said end closure assembly,

said one pair'of closure flaps including at least one segmental cut slot extending through said blank between said inner and outer surfaces and spaced from said nick portions and defining a substantially free side margin of said sealing gusset, said nicks and cut segmental cut slots having a solid blank portion disposed therebetween.

2. The structure as claimed in claim 1, in which said segmental cut slots diverge angularly from said nick portions towards said margin fold line.

3. The structure as claimed in claim 1, in which said nick portions extend angularly in converging relation relative to said segmental out slots.

4. The structure of claim 1, in which said segmental cut slots are disposed intermediately of an inner terminal end of said nick portions.

5. The structure as claimed in claim 1, in which said blank includes a glue-flap panel hingedly connected to a side margin of one of said wall panels, said end margin extending transversely of one end of said glue-flap panel, a

' glue-tab hingedly connected to said glue-flap panel adjacent to the side margin of one of said one pair of closure flaps, the adjacent side margins of said glue-tab and said one closure flap comprising one of said base portions whereby said glue-flap glue-tab will be connected to a closure flap of one of said other pair of said closure flaps when said blank is assembled.

6. The structure as claimed in claim '1, in which the combined height of said other pair of closure flaps is greater than the width of said one pair of closure flaps for forming overlapping sealing gussets extending the width of said one pair of said closure flaps at the margin of said -Wall panel when said closure assembly is closed.

7. In a glued-end carton comprising a body member comprising a one-piece blank and having alternate pairs of rectangular wall panels forming a rectangular cross section and -a coplanar, continuous marginal fold line at one end, the improvement comprising an end closure assembly comprising closure flaps integral with and extending in planar relation from each of said respective wall panels,

adjacent closure flaps including adjacent free side marginal portions at each of said carton corners and '8 terminating in hingedly connected portions, base side marginal portions extending partially into an outer surface portion of said adjacent closure flap and terminating at said continuous, marginal fold line,

one pair of opposed closure flaps including pairs of minute lateral nick portions extending therethrou-gh at the base of said free margin, and at least one segmental out slots spaced by a solid blank portion from said nick portions, said base margin and segmental cut slots defining the margins of a delaminable gusset seal flap hingedly connected to said marginal \fold line.

8. The structure as claimed in claim 7 in which opposed nick portions of said one pair of closure flaps are spaced from said marginal fold line a combined distance at least equal to the width of the flap on which they are formed for producing sealing gusset flaps along the entire width of said one pair of said pair of opposed closure flaps when said carton and closure assembly is closed.

9. In a one-piece delaminable planar blank having an inner and outer side and a glued-end closure and including at least a pair of Wall panels connected on a linear fold line intersecting a transverse, linear marginal fold line, and -a pair of closure flaps hingedly connected to said transverse linear marginal fol-d line, the improvement comprising:

said closure flaps including an adjacent free margin colinear with said fold line between said wall panels continuing into a cut-score line base portion extending partially through the outer side of said blank and terminating at said marginal fold line,

a minute lateral cut-nick portion extending through one of said closure flaps at the terminal end of said free margin and said cut-score line, and at least one cut slot in said one closure 'fiap spaced from said cutnick portion by a solid blank portion and defined by said cut-score line, cut-nick portion and cut slot forming a delaminable sealing gusset web by folding said wall panels substantially normal to each other and the closure flaps into mutual overlying relation.

References Cited by the Examiner UNITED STATES PATENTS 1,723,149 8/1929 Sarnrnot et al. 229-37 1,723,150 8/1929 Gannon 297-37 2,107,096 2/1938 Wisselman 229-37 2,485,235 10/1949 Graf 22937 X 2,516,085 7/1950 Williamson 22937 2,523,488 9/ 1950 Williamson 22937 2,670,128 2/ 1954 Stowitt-s 229-38 2,830,505 4/1958 Guyer 9336.8 3,084,845 4/1963 Myers 93-38 3,094,265 6/1963 Hovland 9337 3,163,347 12/1964 Bixler 229-39 3,182,887 5/1965 Larson 229-37 JOSEPH R. LECLAIR, Primary Examiner.

D. T. MOO RHEAD, Assistant Examiner. 

1. IN A ONE-PIECE, PLANAR, DELAMINABLE, CARTON BLANK HAVING AN INNER AND OUTER SURFACE AND FOR PRODUCING A GLUED END CARTON COMPRISING PAIRS OF ALTERNATIVELY DISPOSED RECTANGULAR WALL PANELS CONNECTED ON MUTUALLY PARALLEL FOLD LINES AND A CONTINUOUS, LINEAR MARGINAL FOLD LINE EXTENDING TRANSVERSELY OF ONE END OF SAID WALL PANELS, AND AN END-CLOSURE ASSEMBLY COMPRISING CUT-AND-SCORED PORTIONS FOR PRODUCING A GLUED-END, CORNER-SEALED CARTON, COMPRISING: PAIRS OF ALTERNATELY DISPOSED END CLOSURE FLAPS HINGEDLY CONNECTED TO SAID MARGINAL FOLD LINE, ONE PAIR OF SAID END CLOSURE FLAPS COMPRISING SIDE MARGINS IN COLINEAR RELATION TO SAID MUTUALLY PARALLEL FOLD LINES AND INCLUDING A FREE TERMINAL PORTION EXTENDING BETWEEN SAID INNER AND OUTER SURFACES AND TERMINATING IN A BASE PORTION EXTENDING PARTIALLY THROUGH SAID OUTER SURFACE OF SAID BLANK AND TERMINATING AT SAID MARGINAL FOLD LINE, SAID ONE PAIR OF END CLOSURE FLAPS INCLUDING MINUTE LATERAL NICK PORTIONS EXTENDING THROUGH SAID FLAPS ADJACENT THE JUNCTURE BETWEEN SAID FREE TERMINAL PORTIONS AND BASE PORTIONS OF SAID SIDE MARGINS FOR ONLY INITIATING DELAMINATION OF A SEALING GUSSET THEREBELOW DURING MANIPULATION AND CLOSING OF SAID END CLOSURE ASSEMBLY. SAID ONE PAIR OF CLOSURE FLAPS INCLUDING AT LEAST ONE SEGMENTAL CUT SLOT EXTENDING THROUGH SAID BLANK BETWEEN SAID INNER AND OUTER SURFACES AND SPACED FROM SAID NICK PORTIONS AND DEFINING A SUBSTANTIALLY FREE SIDE MARGIN OF SAID SEALING GUSSET, SAID NICK AND CUT SEGMENTAL CUT SLOTS HAVING A SOLID BLANK PORTION DISPOSED THEREBETWEEN. 